Garrison Point Fort is a former artillery fort situated at the end of the Garrison Point peninsula at Sheerness on the Isle of Sheppey in Kent. Built in the 1860s in response to concerns about a possible French invasion, it was the last in a series of artillery batteries that had existed on the site since the mid-16th century. The fort's position enabled it to guard the strategic point where the River Medway meets the Thames. It is a rare example of a two-tiered casemated fort – one of only two of that era in the country – with a design that is otherwise similar to that of several of the other forts along the lower Thames.
The government's response to the increased threat was to appoint a Royal Commission on the Defence of the United Kingdom, which published a far-reaching report in 1860. It recommended that many existing forts should be upgraded or rebuilt entirely, and that new forts should be constructed to guard particularly strategic or vulnerable points along the coast. In all, around 70 forts and batteries were constructed around the English coast as a result of the Royal Commission's report.
thumb|De Gomme's fort (centre) alongside the Dockyard ([[Richard Paton, c.1775).]]
Garrison Point had long been fortified. A square blockhouse was constructed there by 1547, during the reign of Henry VIII. It was in the process of being replaced with a new fort when it was destroyed in the June 1667 Raid on the Medway during the Second Anglo-Dutch War. It was rebuilt as a bastion fort by 1669 to a design by Bernard de Gomme, who also designed Tilbury Fort further upriver. Two additional fortifications, the Half Moon Battery and Cavalier Battery, were subsequently added to further strengthen the defences. The Royal Commission recommended that de Gomme's red brick fortification and the two later batteries, which were incapable of withstanding modern guns, should be replaced by an armoured artillery fort on the same site. Its arc of fire would overlap that of Grain Fort and Grain Tower (and later Grain Wing Battery and Dummy Battery) on the other side of the Medway on the Isle of Grain.
Construction and layout
Construction began in February 1861 and continued until the last of its shielding was installed in June 1872, by which time about half of the guns were already in place. The new fort took the form of a semi-circular structure, one of only two built in the 1860s fortification programme (the other being Picklecombe Fort in Cornwall). It had two gun floors, each with 17 granite-faced casemates, in which 36 heavy guns were mounted behind 2,000 tons of iron shields. Another two gun turrets were planned for the roof but were not built. The magazines were located below ground in the basement of the fort. The bulk of the structure was built of brick, with concrete additions. The walls and piers are thick. The semi-circular row of casemates is closed off to the rear by a row of defensible buildings constructed from ashlar blocks of Kentish ragstone, with loopholes and gun ports in the flanks to facilitate close defence of the fort. A parade ground occupied the middle of the fort.
Current status
left|thumb|Garrison Point Fort, 2008
The fort has been a Grade II listed building since 1977 and is part of the wider system of the Sheerness defences, listed as a scheduled monument. It is owned by Medway Ports Ltd, the operators of the Sheerness Docks, and is not publicly accessible as it lies within the port area. Some alterations have been made to the fort to enable its use in connection with the port. It was used for a time in the 1980s as a terminal for a now-defunct ferry service to the Continent, which involved fitting a walkway to the ferries through one of the casemates.
Garrison Point Fort is reportedly in a state of "slow decay" which has led it to be listed on the Heritage at Risk Register. Although the interior has been largely stripped out, traces remain of the original fittings. A considerable amount remains of the Brennan Torpedo station and its launching rails, though it is corroding badly. While the fort's structure is still basically intact its roof and much of its interior are derelict and decaying.